TABLE 1

Bacterial species associated with colon cancera

Name(s)RelationshipReference(s)
Citrobacter rodentiumMin mice inoculated with this species had a 4-fold increase in colonic tumors. Found only in mice.25
Enterococcus faecalisProduces superoxide and hydrogen peroxide, both of which can damage DNA in epithelial cells26, 27
Clostridium cluster XVIa (Clostridium scindens, C. hiranonis, and C. hylemonae) and Clostridium cluster XI (C. sordellii)Can produce secondary bile acids, such as deoxycholic acid (DOC), that increase tumor burden in wild-type male B6.129PF2/J mice28, 29
Acidovorax speciesAssociated with increased risk for colon cancer and may act as a pathogen by increased metabolism of nitroaromatic compounds30
Enterotoxigenic Bacteroides fragilisProduces a toxin that caused colitis and tumors in multiple intestinal neoplasia (MinApc716+/−) mice through an IL-17-dependent pathway31
Streptococcus gallolyticusPresent in approximately 20 to 50% of colon tumors compared to less than 5% of normal tissue in CRC patients. Patients with high counts of S. gallolyticus have increased expression of proinflammatory cytokines, including interleukin-1 (IL-1) and cyclooxygenase-2 (COX-2).32
Escherichia coli NC101Produces genotoxic colibactin that led to increased tumor burden in AOM/Il10−/− mice33
Fusobacterium nucleatumInduces hyperproliferation of human colon cancer cell lines through binding of its FadA adhesin to E-cadherin. Also, promotes immune evasion of tumors through binding of its Fap2 adhesin to TIGIT receptors on immune cells.34, 35, 37, 38
Akkermansia muciniphilaMucin-degrading species were found in 4-fold-larger amounts in CRC colons than in normal colons36
  • a Species names, details of association, and references are listed in chronological order.